Most major carriers have some way of communicating with them for this purpose. Level(3) uses BGP community 9999 for a peer of theirs to issue /32 routes to their black hole router. Global Crossing uses an eBGP multi-hop peer for these types of advertisements and others have their mechanisms as well. On the flip side, through route-maps you could setup a community for your customers to advertise to you traffic they wish to null, of course you must take great care when doing this as to not allow something that could really screw your network. In our network, all of our /32 nulls have a tag applied from our black hole router, which gets propagated via OSPF then eventually gets handed off to our peers using either a community or multi-hop neighbor. --- Jordan Medlen Chief Technology Officer and Architect Sago Networks -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Payam Tarverdyan Chychi Sent: Sunday, August 13, 2006 2:24 PM To: Michael Nicks Cc: nanog@nanog.org Subject: Re: [Full-disclosure] what can be done with botnet C&C's? Though placing a /32 to a discarded interface helps the situation, you are now fully disabling your client that uses the /32... I do agree that it definitely helps the situation... specially when the attack is a few mil pps or perhaps even few gigs/sec in which case a customer /32 or bigger. being down is about 100x better then your network being down. so my question is then how do you use the same method for your peering sessions (assuming you do peering on a private or public level)... seeing how 95% of peers will not allow such specific entries such as /32 into their tables... so in case of an attack you are left with either having to take down the peering session or stop advertising the prefix though that peer. Just curious as to how you go about it... cheers, -Payam
I hate to stir the flames again, but this idea sounds a lot like RBLs. :)
All kidding aside, I'm curious as to when we will reach the point where the devices of our networks will be able to share information regarding sporadic bursts or predefined traffic patterns in network traffic within a certain time frame, determine it is a related outgoing (or incoming) attack, and mitigate/stop the traffic. I think it certainly is possible to accomplish this on a per-router level, but being able to have the devices communicate and share information between one another is a completely separate thing. (New protocol perhaps.)
The only real method that I really have in my toolkit to stop incoming DDoS on a AS-wide perspective is originating a /32 within an AS with a next-hop of a discard interface.
Something similar to that nature but more flexible and designed for the sole purpose of preventing/stopping abuse would be a very nice
feature.
Cheers. -Michael
-- Michael Nicks Network Engineer KanREN e: mtnicks@kanren.net o: +1-785-856-9800 x221 m: +1-913-378-6516
Payam Tarverdyan Chychi wrote:
I've been reading on this subject for the last several weeks and it seems as if everyone just like to come up with out of the box ideas that are not realistic for today's network environments
J.Oquendo, thanks for the Smurf example . as there are still admins/engineers at large networks that have no clue as to what they are doing. so QoS is for sure out of the question.. at least at this time.
Depending on agents to take actions and protecting our networks is even a bigger joke. Back in late 90s where kiddies were using the simplest types of C&C, open wide irc networks with visible Channels and no encryptions. and agents couldn't do anything unless the attack was big enough to take down Amazon, yahoo, Microsoft or some other major provider with enough $$$ to start an investigation.
So what makes you think that agents are of any help in today's world where c&c have gotten so much more sophisticated, use backup private servers, encryption, tunneling and much much more..
In my opinion, the only way to really start cracking down on c&c and put an end to it is the cooperation of major ISP's. I realize that most isp's cant/wont setup a security team to just investigate c&c / attacks (would this really fall under the Abuse team?) but perhaps If all major networks worked together and created a active db list of c&c found either on their networks or attacking ones network. then it would be much much easier to trace back c&c and dispose of them.
Unfortunately, we don't live in a perfect world and most isp's hate sharing any information. I guess its better for them to have a bigger ego than a safer / more stable network.
Please feel free to correct me if I am wrong.
-Payam
-- -- Payam Tarverdyan Chychi Network Analyst